Enclosed circuit interrupter



July 27, 1965 NQRDEN 3,197,582

ENCLOSED CIRCUIT INTERRUPTER Filed July 50, 1962 3 Sheets-Sheet 2INVENTOR. ALEXANDER R. NORDEN 96 ATTORNEY III/11111111 July 27, 1965 A.R. NORDEN 3,197,582

ENCLOSED CIRCUIT INTERRUPTER Filed July 30, 1962 3 Sheets-Sheet 3 4fl2 II I 68 6 1 n V z l f I 5E FIG. 7

INVENTOR.

ALEXANDER R. NORDEN ATTORNEY Unitcd States Patent 3,197,532 EPQCLQSEBCTRCUHT INTERRUPTER Alexander Norden, New Yorlr, N.Y., assi nor toFederal Pacific Electric Company, a corporation of Delaware File-d .luly3Q, 1%.2, Ser. No. 213,364 6 Claims. (Cl. Elwi -h) The resent inventionrelates generally to enclosed circuit interrupters having operatinghandles disposed ex ernally of the enclosure and more particularly tothe operating and interlocking mechanisms for such devices.

Overcentering mechanisms are used in circuit interrupters to gi e snapopening and closing of the contacts. in this type of mechanism a sprinor set of springs connects the handle and an overcentering togglelinkage connected to the contact arms. The springs are used to oper atethe toggle linkage, in response to handle movements, to thereby controlthe movement of the switch contacts. On some occasions, the contacts ofthe switch may stick together forming what is known in the art as stickwelds. An object of this invention is to provide an interrupter havingan improved handle operated overcentering mechanism for enabling theinterrupter contacts to be opened in the event of contact-to-contactwelds.

An additiona problem encountered with the use of overcentering mechanismwas the possibility of breakage of the overcentering springs or loss ofspring tension for any reason. While such contingency is relativelyremote, it is an important safety consideration that some positive meansbe provided for insuring opening of the contacts by operation of thehandle without depending upon the springs. An object of this inventionis to provide an in terrupter having an improved overcentering mechanismwhich assures positive opening of the contacts.

Yet another object of the invention is the provision of an enclosedcircuit interrupter having interlock means which is responsive to theposition of the enclosure cover and which prevents closing of thecontacts when the cover of the enclosure is open.

The above and other objects and advantages are achieved in anillustrative embodiment of the invention described in detail below withreference to the accompanying drawings. In those drawings:

*"lG. l is a plan view of an enclosed circuit interrupter with theenclosure door in the closed position;

FIG. 2 is a side elevation of the apparatus of PEG. 1, with theenclosure door open, in partial section and with some parts broken away,showing the enclosure cover interlocking mechanism in its operativeposition;

FIG. 3 is a fragmentary side elevation of the contact operatingmechanism of the circuit interrupter, on an enlarged scale, in thecontact open position;

FIG. 4 is a view similar to PEG. 3 showing the mechanism partiallyoperated in the on direction;

PEG. 5 is a view similar to FIG. 3 showing the mechanism in the full onor contact closed position;

PEG. 6 is an end view of the apparatus of PEG. 2, with the enclosuredoor closed, as viewed in the direction of the arrow 6 in FIG. 2, inpartial section and with some parts broken away for simplicity andclarity; and,

FIG. 7 is a View similar to PEG. 3 showing the operation of the positivedrive mechanism in assisting the separation of the contacts.

Referring now to the drawings, a switch 2%, as one "ice form of circuitinterrupter, is shown mounted in a metal enclosure 22 having a cover 23connected by a hinge 24 to the enclosure body 25. Operating handle 26and a portion of the upper cover plate 2% of the switch Ztl are disposedwithin the access opening 30 provided in the cover.

Switch Jill is provided with a base of insulation 32 which hasupstanding walls (only one shown) to which the cover plate 28 issecured. A two-part operating handle 26 is pivotally mounted on plate 23and has a main hub 36 above the plate 23 and a secondary hub 38 belowthe plate. Lower hub 3% is provided with an offset portion 4i?containing a recess Referring to FIG. 3 switch 2i) has operating means44 which includes an operator 45 that is generally U-shaped (FIG. 6).The bight portion of operator 45 has a central pin 48 secured thereto.Pin 4-3 cooperates with recess 42 to pivot the operator 45 in responseto movement of handle 26. The operator has a pair of spaced legs 5t)tiat are pivoted on pins 5'2 secured to the main switch frame 54, thisbeing two metal plates fixed to base 32 (P16. 6). Arcuate clearanceslots 5t: are formed in each of the legs 54) adjacent the bight portion4-6. Two pairs of spaced, opposed rollers 53, so are mounted on each ofthe operator legs 5i), by pins 62, between the pivots 52 and slots 56.The function of these rollers will be more fully explained later.

A link 64 is pivoted, adjacent each leg Stl, on a pin which passesthrough the arcuate slot 56 in the operator 4d. The pins 66 are attachedto the frame 54. The other ends of the links 64- are joined together bya steppeddiameter pin 70 which ties the links together and which has alarger diameter portion '71 that functions as a cam follower or driver,as will be explained later. Stops 63, to limit travel of the linlrs 64in the closed contact position, are formed on the frame 54. A pair ofovercentering springs 72 (see FIG. 6) are fixed at one end to the narrowdiameter portions of pin 76 and, at their other end, to a bracket 74secured to the underside of bight as of the operator The bracket end ofthe springs 72. is above the pivots 66 of the links 64. The extremitiesof the springs 72 define the line of action of the springs.

Contact arm carriers 76, one for each pole of the switch, are secured toinsulated switch shaft 75 which is common to all poles. The operatingmechanism 44 is at the center pole of the illustrative embodiment andthe operating forces are transmitted to the outboard poles by shaft 7%which passes through the frame 54 and is journaled at 7% at each end inthe insulated body 32 of the switch 249. The c nter pole contact armcarrier 76 (FIG. 6) is positioned between the legs 59 of the operator 45and has a planar cam surface and a curvilinear carn surface 82 (FIG. 3)for cooperation with the cam surface 71 of pin 7%. Link 64- and carrier76, pivoted at and 79 respectively, form a toggle linkage 83. The togglehas a knee which is a lost motion coupling formed by pin 70 and thecarrier cam surfaces 84) and 82.

Each pole of the switch has a tri-furcated contact arm which is pivotedat 86 on its contact arm carrier 76. Contact arm 84 has the movablecontact 83 affixed to one leg of the arm and has a connecting braid 93secured to another leg Mb. The braid 9t) and contact arm portion 84.5are receivable in a recess 91 in the base 32 of the switch. Contactpressure is provided by overtravel spring $2 which reacts between thecontact arm caral rier '76 and leg 840 of the contact arm. The travel ofthe contact arm 84 relative to the contact arm carrier '76 in the openposition is limited by the engagement of the carrier and a leg 34!) ofthe contact arm as best seen in FIG. 3. The circuit through each pole ofthe switch 2t), when the contacts are closed, is as follows; throughconnector 94 to conductor 96, stationary contact 98, movable contact 88,contact arm braid 9ft, and lug ltitl to which the external connectionmay be made in conventional manner.

Contact position-responsive interlock means Th2 are provided to preventclosing of the contacts when the enclosure cover 23 is open. Theinter-lock 162 includes an arm 10d of insulation, secured to the switchshaft its to which the contact arm carrier '76 are attached. Referringto FIGS. 2 and 6, arm 1% has a projection 1% which extends laterallythrough an aperture in the interior wall lift of the base 32. Theprojection res has a flat under surface Tilda which cooperates with astop or cam member Stilt; pivoted at 111 on an interior wall 116. Stop1% has an end surface W841 which engages the arm surface 106a when theinterlock is actuated. Stop 1% is resiliently'urged in the arm 14Mengaging direction by spring 112. Stop actuator 114 is mounted forreciprocating movement along wall 116 and is biased upwardly in FIG. 2,in the cover 23 engaging direction, by spring llliii. The lower end ofthe actuator 114 carries a flat member 114a that is between opposed arms19812 and 1380 of the stop. Arm 1831') has a rounded projection 168dagainst which the actuator member 114a presses. The upper end 1141) ofthe actuator is adapted to engage the cover 23 as in FIG. 6. When thecover is closed, actuator 114- is depressed causing stop llt fi to bepivoted to a non-interfering position (shown in dotted lines in FIG. 2)from the arm engaging position (shown in solid lines in FIG. 2) whereinit interferes with rotation of the switch shaft 78 to the contact closedposition. The positive drive feature of the overcentering mechanism, tobe described below, acts only in the contact-opening direction andaccordingly does not conflict with the operation of thi interlockmechanism.

Having described the embodiment of the invention illustrated in thedrawings, a description of the operation thereof follows. Before thecircuit interrupter 20 may be shifted from a contact open to a contactclosed position, it is necessary for the cover 23 to be closed todeactivate the interlock 1692. When the cover is closed the actuatorllld pivots stop lltlti to a non-obstructing position clear of the armprojection 1% as shown in dotted lines in FIG. 2.

Referring now to FIG. 3, the interrupter 2b is shown in the contact openposition. When handle 26 is rotated the operating means 44 is actuatedand operator 45 pivots to the left. Rollers 66 on the operator 45, whichact against links 64 in the contact closing direction, may be calledcontact-closing rollers. These rollers are driven against the links 64and assist the overcentering springs '72 in driving the knee pin '70 ofthe toggle 83 in the toggle erecting direction. In FIG. 4 the links 64have been swung rom their rest position (FIG. 3) and have been shiftednearly into line with the line of action of the springs '72,. Duringthis motion, springs '72 are "stretched, and thus develop stored energythat is later released to close the contacts. Continued pivotal movementof the operator in the contact closing direction brings the upper end ofthe overcentering springs 72 across the line of centers on, 7d of thetoggle link 64. When the upper ends of the springs have passedovercenter sufliciently, the knee pin 7th leaves the planar surfaces $9and crosses to the curvilinear surfaces 82 The links 64 continue movingalong cam surfaces 82 with a snap action under the force of the springs'72. The force of the springs '72 drives the pin 7t along the camsurfaces 82 accelerating the contact carrier '76 and contact arms 84 inthe contact closing direction. Springs 92 that provide contact pressureare compressed during the contactclosing motion of links 64 and contactcarrier 76. The contour of cam surfaces 82 in relation to links 6provides mechanical advantage after initial contact engagement,producing progressive compression of the contact pressure springs 9 2.In FIG. 5, which shows the fully closed position, the links as aresubstantially normal to the portion of cam surfaces 82 which theyengage. Further travel of links 64 is prevented by interposed stops Theposition of links M normal to the curvilinear surfaces d2 maintains thecontact carriers rs locked in the on position. Springs 72 provideclockwise bias holding links 64 against stops 63, thus holding the linksas in their locking position.

To open the contacts the handle is driven from the on position towardthe elf position, in the direction of the arrow near part til in FIG. 5.Operator 45 is pivoted to the right from its position in FIG. 5. Rollers53 bear against the links 6 3 to shift the links sa toward alignmentwith springs '72. As this occurs, the upper ends of springs '72 areshifted toward pivots 6d of links as and, in this motion, the tension insprings 72 is increased Continued movement of the handle brings theupper ends of springs 72 overcenter. Links 64 are then carriedovercenter of the centers 66, 7t and knee pin 7th is driven sharplyagainst the planar surface 8t? thus driving the contact carriers 76 tothe open position with a snap-action. At the completion of this stroke,links 64 are biased against rollers e and in this position links 64 arenormal to the cam surfaces $19 of the contact carrier '76. Thi locks thecontact carriers in the open position. The limiting position of stoprollers 6ft is reached when rollers 58 engage the opposite edges oflinks 64.

in the event that the overcentering springs 72 should be weakened, breakor become disabled for some reason while the contacts are closed, or ifa stick weld condition of the contacts should develop, it is stillpossible, in the illustrative embodiment, to open the contacts. Movementof the operator 55 in the opening direction drives the rollers 38against the links 64 (FIG. 7) and moves the pin 7% clear of the camsurfaces 82. When the carriers are retained in the on position becauseof contactto-contact welding, the pin 7th may be driven directly againstthe planar surface of the contact arm carrier means 76. Because of thepositive mechanical connection, sufficient force to break the weld andto return the contact arm to the open position is developed withoutdependence on the springs.

It was noted that roller so helps to bring the springs and links 64 intoalignment in a contact-closing operation of the handle. it would not benecessary for roller so to be movably supported on operator 45 if itsonly function were to act as a stop. In that event it would be possibleto rely solely on the operator 45 to shift the upper ends of springs 72past the line of centers 66, 7t) of link dd. However, such anarrangement would compel considerably greater elongation of the springswhich might then be stressed excessively. The fact that roller 69carries links M- to the left (FIG. 3) as the springs are shifted towardtheir overcentering relationship to links greatly simplifies the servicerequirement of the springs. The foregoing analysis is pertinent inconnection with the action of roller 58 in shifting links 64- into linewith the springs as the springs are being stressed by initial returnmovement of the operator 45 in the off direction.

When the cover is open (FIG. 2), the end rear of stop MP8 projectsbeneath the projection 1&6 and prevents movement of switch shaft 78beyond the position shown in phantom in FIG. 2. When the shaft 78 isarrested the contacts are positively prevented from closing.

iowever, the operator 45 is free to move to the on position by virtue ofits spring coupling to the switch shaft 78. The spring connectionbetween the handle 26 and the link 64 does not function as anover-centering mechanism when the switch shaft is obstructed. Instead,springs 72 return the handle 26 to its off position, when released.

The above described embodiment of the invention fulfills the objectswith the provision of a relatively simple structure capable of repeatedoperations with a high degree of reliability and safety for theoperating personnel.

It will be apparent that the mechanism described above, While being thepresently preferred embodiment of the invention, is subject to a widelatitude of modification and varied applications by those skilled in theart, so that this invention should be construed in accordance with itsfull spirit and scope.

What I claim is:

1. Enclosed switching apparatus having an enclosure, a door hingedlymounted on said enclosure, switching apparatus mounted in saidenclosure, said apparatus being operable with said enclosure doorclosed, said apparatus including a movable contact and a stationarycontact, a switch shaft pivoted in said apparatus, said movable contactbeing carried by said shaft, manual operating means forming part of saidswitching apparatus and being movable between on and off positions formoving said switch shaft between open and closed contact positions, saidoperating means including a manual operator fixed to said switchingapparatus and overcentering spring means operatively connected to saidshaft, and interlocking means engageable with said shaft, saidinterlocking means being responsive to the position of said enclosuredoor to obstruct movement of said shaft in the contact closing directionwhen said enclosure door is open, so that the operator may bemanipulated to the on position against the bias of said spring meansdespite obstruction of the switch shaft.

2. Apparatus according to claim 1 wherein said interlocking meansincludes a cam member secured to said switch shaft, a pivoted stopmember resilientiy urged into engagement with said cam member toobstruct movement of said shaft in the circuit closing direction, doorposition sensing means including a rod mounted for movement between anextended position and a retracted position, said rod being adapted toengage said door at one end and to engage said pivoted stop member atthe other, and means resiliently urging said rod to its extendedposition, said rod being driven into its retracted position by the doorin its closed position and thereby pivoting said stop member clear ofsaid cam member on said switch shaft to allow movement of said contactsin the circuit closed direction.

3. Enclosed switching apparatus having an enclosure, a door hingedlymounted on said enclosure, switching apparatus mounted in saidenclosure, said apparatu being operable with said enclosure door closed,said apparatus including a movable contact and a stationary contact, aswitch shaft pivoted in said apparatus, said movable contact beingcarried by said shaft, manual operating means forming part of saidswitching and being movable between on and off positions for moving saidswitch shaft between open and closed contact positions, said operatingmeans including a manual operator fixed to said switching apparatus andovercenter-ing spring means operatively connected to said shaft, andinterlocking means engageable with said shaft, said interiocking meansbeing responsive to the position of said enclosure door to obstructmovement of said shaft in the contact closing direction when saidenclosure door is open, so that the operator may be manipulated to theon position despite obstruction of the switch shaft, said spring meansbeing arranged to bias the manual operator away from the on positionwhen the switch shaft is obstructed.

4. Switching apparatus including a movable contact arm, a companioncontact engaged thereby in the closed condition of the switchingapparatus, and mechanism for operating said movable contact arm toeffect quick closing and quick opening of the contacts, said mechanismincluding a two-part cam operably connected to said contact arm, a linkhaving a fixed pivot at one end and having an active opposite end, anoperator movable relative to said fixed pivot and reversely operable incontactclosing and contact-opening strokes, an overcentering springconnected at its extremities to said operator and to said active end ofthe link, respectively, said operator being arranged to shift the springacross said fixed pivot reciprocably for effecting quick overcenteredstrokes of the link in response to said strokes of the operator, andsaid link being arranged to cooperate successively with the two parts ofsaid cam in each stroke of overcentered operation of the link and havinga range of lostmotion between separation of the link from one part ofthe cam and engagement with the other during each stroke of overcenteredoperation of the link, stop means limiting the positions of said link ateach end of the stroke thereof, said parts of said cam having surfaceportions engaged by said link, said cam surface portions divergingtoward said fixed pivot of said link, said parts of said cam havingportions engaged by said link in said end positions which cam portionsare substantially transverse to a line between the pivot of the link andthe engaged part of the link for locking the link against any operatingeffect by said cam and thereby locking the contact arm.

5. A circuit interrupter including a movable contact, a companioncontact engaged thereby in the closed condition of the circuitinterrupter, mechanism for operating said movable contact to effectquick closing and quick opening of the contacts, said mechanismincluding a link having a fixed pivot at one end and having an activeopposite end, an operator movable relative to said fixed pivot andreversely operable in contact-closing and contact-opening strokes, anovercentering spring connected at its extremities to said operator andto said active end of the link, respectively, said extremities definingthe line of action of said spring, said operator being arranged to shiftits end of the spring across said fixed pivot reciprocably, acontact-carrier fcr said movable contact, a cam fixed to said contactcarrier and engagea-ble by said link upon overcentering of the springrelative thereto for driving the contacts open and closed, and stopmeans for limiting the travel of said link in the contact openingstroke, said cam having a contour that is transverse to said link whenthe link is arrested by said stop means so as to lock the contactcarrier at the end of said contact opening stroke.

6. Switching apparatus including a movable contact arm, a companioncontact engaged thereby in the closed condition of the switchingapparatus, resilient means for providing contact pressure when saidswitching apparatus is in its closed circuit condition, and mechanismfor operating said movable contact arm to effect quick cl0sing and quickopening of the contacts, said mechanism including cam means operablyconnected to said contact arm, a first portion of said cam mean beingemployed in closing said contacts and a second portion of said cam meansbeing employed in opening said contacts, a link having a fixed pivot atone end and having an active end for engaging said portions of said cammeans, said first portion of said cam means having a substantiallycurvilinear surface along which said active end of said link travelsfrom a point of initial contact to an end point, said second portion ofsaid cam means having a substantially planar surface along which saidactive end of said link travels from the point of initial contact to anend point, the tangent to said surface of said first portion at said endpoint forming an acute angle with the tangent to said cam surface ofsaid second portion, said link being substantially perpendicular to theengaged cam surface at both said end points, an operator movablerelative to said fixed pivot and reversely oper- '2" able incontact-closing and contactopening strokes, an overeentering springconnected at its extremities to said operator and to said active end ofthe link, respectively, said operator being arranged to shift the springacross said fixed pivot recipr-ocably for effecting quick overcenteredstrokes of the link in response to said strokes of the operator, andsaid link being arranged to cooperate successively With said firstportion and said second portion of said cam means in each stroke ofovercenter operation of the link and having a range of lost-motionbetween separation of the link from one portion of the cam andengagement with the other during each stroke of overcenter-ed operation,said link and said cam means 0 if) cooperating at both said end pointsto lock said contact arm against movement.

References (Cited by the Examiner UNIT ED STATES PATENTS 2,442,464 6/44Link 200-116 2,468,645 4/49 Steinmayer 340222 2,937,254 2/57 Ericson 200114 FOREIGN PATENTS 192,220 2/23 Great Brita n.

734,845 8/55 Great Britain.

BERNARD A. GILHEANY, Primary Examinelz

1. ENCLOSED SWITCHING APPARATUS HAVING AN ELCLOSURE, A DOOR HINGEDLYMOUNTED ON SAID ENCLOSURE, SWITCHING APPARATUS MOUNTED IN SAIDENCLOSURE, DOOR CLOSED, SAID APPARAOPERABLE WITH SAID ENCLOSURE DOORCLOSED, SAID APPARATUS INCLUDING A MOVABLE CONTACT AND A STATIONARYCONTACT, A SWITCH SHAFT PIVOTED IN SAID APPARATUS, SAID MOVABLE CONTACTBEING CARRIED BY SAID SHAFT, MANUAL OPERATING MEANS FORMING PART OF SAIDSWITCHING APPARATUS AND BEING MOVABLE BETWEEN "ON" AND "OFF" POSITIONSFOR MOVING SAID SWITCH SHAFT BETWEEN OPEN AND CLOSED CONTACT POSITIONS,SAID OPERATING MEANS INCLUDING A MANUAL OPERATOR FIXED TO SAID SWITCHINGAPPARATUS AND OVERCENTERING SPRING MEANS OPERATIVELY CONNECTED TO SAIDSHAFT, AND INTERLOCKING MEANS ENGAGEABLE WITH SAID SHAFT, SAIDINTERLOCKING MEANS BEING RESPONSIVE TO THE POSITION OF SAID ENCLOSUREDOOR TO OBSTRUCT MOVEMENT OF SAID SHAFT IN THE CONTACT CLOSING DIRECTIONWHEN SAID ENCLOSURE DOOR IS OPEN, SO THAT THE OPERATOR MAY BEMANIPULATED TO THE "ON" POSITION AGAINST THE BIAS OF SAID SPRING MEANSDESPITE OBSTRUCTION OF THE SWITCH SHAFT.